Spectral analysis of heart rate variability in patients with irritable bowel syndrome

BACKGROUND

Autonomic dysfunction, both adrenergic and cholinergic, has been associated with the irritable bowel syndrome (IBS). The accuracy of the methods in use, however, has been limited by the need for active co-operation by the patients, with consequent difficulties in standardization. The aim of this study was to investigate the function of the autonomic nervous system in patients with IBS by using spectral analysis of the heart rate variability, an accurate method depending very little on patient cooperation.

METHODS

Eighteen patients with IBS were compared with 36 sex- and age-matched controls. Spectral analysis of heart rate variability was performed to quantify sympathetic and parasympathetic nerve activity.

RESULTS

The patients with IBS had significantly higher sympathetic activity than controls (P = 0.005). There was no significant (P = 0.308) increase in parasympathetic activity. There were no significant differences in heart rate or blood pressure between the patients and controls.

CONCLUSION

Spectral analysis of heart rate variability has been used to assess the function of the autonomic nervous system in patients with IBS. IBS patients have significantly increased symphathetic activity, whereas parasympathetic activity does not differ from that of controls.

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

[Open surgical therapy of functional disorders of the rectum and pelvic floor]

An overview is given of common transabdominal procedures for functional disorders of the rectum and pelvic floor which are caused by degenerative morphological changes, and termed pelvic floor insufficiency. Only the transabdominal approach permits a comprehensive and pathophysiological repair of changes associated with the disorder. Own results and a review of the literature confirm a superior functional outcome and low recurrence rates with a combined procedure consisting of rectopexy, colonic resection and pelvic floor repair.

[Neurophysiologic diagnosis in proctology]

Functional diagnostic exploration in proctology is ever-expanding and becoming more differentiating. Neurophysiologic examinations can take over an essential share. They have in part already been introduced into routine diagnostic workup. Both afference and efference, as well as the muscular system can be investigated in functional neurologic disorders of the pelvic floor. The electromyogram using concentric needle electrodes constitutes the most significant tool. It provides us with a better verification of the neurogenic lesion, and enables us to discriminate between acute and chronic and comment on severity and prognosis. The diagnostic program is additionally supplemented by motor and sensory evoked potentials, electroneurography of the pudendal nerve, and measurements of vegetative nerve paths.

Pain is temporally related to eating but not to defaecation in the irritable bowel syndrome (IBS). Patients' description of diarrhea, constipation and symptom variation during a prospective 6-week study

OBJECTIVES

To study the intensity and variation of pain and its temporal relation to eating and defaecation. Furthermore, what irritable bowel (IBS) patients mean by constipation and diarrhea and how bowel symptoms vary.

DESIGN

Prospective daily symptom recording over 6 weeks.

SETTING

The primary catchment area of University Hospital of Linköping.

PARTICIPANTS

Eighty consecutive patients fulfilling the Rome criteria; 63 finished the study.

RESULTS

Fifty-nine of 63 patients recorded an average of 29 pain periods and 24 days with pain during the 6 weeks. Over-all pain burden decreased slightly over the study period. At inclusion 38 (64%) patients claimed that pain was relieved by defaecation. However, on average, only 10% of each patient's recorded pain periods were relieved by defaecation. At inclusion 29 (49%) patients claimed postprandial worsening of pain. On average, 50% of each patient's recorded pain periods worsened postprandially. The patients defined constipation as hard stools and diarrhea as loose stools and urgency. Stool frequency did not differ. Bowel symptoms varied within, but not between, fortnightly periods.

CONCLUSIONS

Postprandial worsening of pain should be included as a criterion in the clinical definition of IBS while the criterion 'pain relieved by defaecation' should be re-evaluated. IBS patients can probably be divided into subgroups based on stool consistency, not frequency. Daily records are superior to structured clinical interviews or questionnaires for a detailed study of symptoms in IBS.

The relationship between psychological distress and gastrointestinal symptoms in women with irritable bowel syndrome

BACKGROUND

Individuals with irritable bowel syndrome (IBS) are reported to experience more symptoms compatible with psychopathologic disorders, abnormal personality traits, and psychological distress. Conversely, individuals with psychiatric disorders report higher levels of gastrointestinal (GI) symptoms compatible with IBS. Thus, psychological distress may contribute to GI symptoms in individuals with IBS.

OBJECTIVES

To examine psychological distress in women with IBS, women with similar GI symptoms but not diagnosed (IBS nonpatients, IBS-NP), and asymptomatic Control women.

METHODS

The women (N=97) were interviewed, completed questionnaires, and maintained daily diaries for 2 months. Across-women and within-woman analyses were used to calculate the results.

RESULTS

The IBS and IBS-NP groups had a higher percentage of lifetime psychopathology and recalled psychological distress. At least 40% of the women in the IBS and IBS-NP groups had positive relationships between daily psychological distress and daily GI symptoms.

CONCLUSIONS

Psychological distress is an important component of the IBS symptom experience and should be considered when treatment strategies are designed.

Bran: may irritate irritable bowel

The irritable gut is known to be hypersensitive, and it is reasonable to suspect that patients with the disorder might be hyperreactive to agents that stimulate or irritate it. This appears to be a possible explanation for the adverse effects of bran on hospital patients with this disorder, but we do not yet know how this product affects community IBS sufferers. We cannot ignore the fact that fiber and bran have major beneficial effects in other areas, not least in the reduction of colonic carcinoma. In conclusion, it is probably best to recommend that patients with IBS be left to judge for themselves whether bran helps or exacerbates their symptoms, but there is enough evidence to suggest that the current dogma of routinely treating all IBS sufferers with bran should be challenged. Proprietary sources of fiber, such as ispaghula, may be more appropriate for those IBS subjects (for example, constipated) for whom fiber supplementation is believed justified.

Postpartum fecal incontinence is more common in women with irritable bowel syndrome

PURPOSE

Anal sphincter damage can occur during vaginal delivery and may lead to impairment of fecal continence. The aim of this study was to determine the influence of irritable bowel syndrome on symptoms of fecal incontinence following first vaginal delivery.

METHODS

A prospective, observational study was performed before delivery, six weeks, and six months following delivery in primiparous women. A bowel function questionnaire was completed, and anal vector manometry, mucosal electrosensitivity, pudendal nerve terminal motor latency, and anal endosonography were performed. A total of 208 women were assessed before and after delivery, and 104 primigravid women were studied after delivery only. A total of 34 of 312 (11 percent) had an existing diagnosis of irritable bowel syndrome.

RESULTS

The prevalence of abnormal manometry or endosonography was similar in women with and without irritable bowel syndrome. However, six weeks after delivery, women with irritable bowel syndrome had a higher incidence of defecatory urgency (64 percent) and loss of control of flatus (35 percent) compared with those without (urgency, 10 percent, P < 0.001; flatus, 13 percent, P = 0.007). The incidence of frank fecal incontinence was similar in the two groups. Women with IBS had increased mucosal sensitivity to electrical stimulation of the upper anal canal both before and after delivery.

CONCLUSION

Women with IBS are more likely to experience subjective alteration of fecal continence postpartum compared with the healthy primigravid population, but they are not at increased risk of anal sphincter injury.

The constipated stomach. An underdiagnosed problem in patients with abdominal pain?

The number of dyspeptic patients with upper abdominal pain that are referred for investigation is increasing and will undoubtedly continue to increase, because these days peptic ulcer disease is increasingly becoming a primary care management issue, the specialist being left to deal with the patients who cannot be helped by antibiotics and antisecretory drugs prescribed by their general practitioner. Many of these patients are referred for an upper endoscopy to rule out organic disease. Carefully taken history, however, shows that a great number of those dyspeptics, on the basis of their clinical manifestations, do have a functional gastrointestinal disorder, representing the 'irritable gut'. A probable better term reflecting the direct relation is the syndrome of 'the constipated stomach'. In our opinion these patients are an important and increasing clinical problem for general practitioners, gastroenterologists, surgeons and physicians. The aim of this article is to make the practitioner aware of advancements in understanding pathophysiologic and psychosocial processes, as well as to give an overview of the great overlap between many functional gastrointestinal disorders, the important role of history-taking and some insights into the functional rectal outlet syndrome.

Adequate relief as an endpoint in clinical trials in irritable bowel syndrome

Irritable bowel syndrome is characterized by recurrent abdominal pain and altered bowel function. In designing studies to evaluate new treatments for this disease, however, it is difficult to select appropriate endpoints to reflect improvement in the range of symptoms of the syndrome. In the present study we evaluated the parameter of adequate relief of abdominal pain and discomfort, as perceived by the patients, as a key endpoint for efficacy in the treatment of patients with irritable bowel syndrome. Abdominal pain and bowel function data were collected daily from 370 patients with the disease during treatment with placebo or a novel potent 5HT3 receptor antagonist. Once every 7 days adequate relief of pain and discomfort was assessed. Quality-of-life data were collected using self-administered questionnaires. The endpoint of adequate relief was significantly (P < 0.05) correlated with improvement in pain severity scores, percentage of pain-free days, percentage of days with urgency, improvement in stool frequency and consistency, and quality-of-life parameters. Adequate relief of pain and discomfort is significantly correlated with changes in multiple parameters associated with irritable bowel syndrome and can be used as an endpoint for assessing response to therapy in these patients.

Women with gastrointestinal symptoms: implications for nursing research and practice

Irritable bowel syndrome and functional bowel disorder are diagnoses used to describe chronic GI symptoms for which no overt pathological condition can be identified. Symptoms are more common in women and are frequently followed in gastroenterology clinics. The purpose of this article is to provide an overview of the research linking GI symptoms and reproductive cycling and to discuss implications for practice. GIGl symptoms such as stomach pain and nausea are highest during menses compared with other cycle phases; also, stool consistency is loosest at menses. This pattern is present in control subjects. In women with irritable bowel syndrome the same pattern is seen but with higher symptom intensity. Although animal studies have demonstrated that estrogen and progesterone modulate contractile function of some GI segments. In humans, symptoms are highest when these hormones are at the lowest levels. Thus, symptoms in women may be related to decreasing ovarian hormone levels or to other circulating hormones or factors which vary with the menstrual cycle. Additionally, other factors such as stress aggravate symptoms. Therapeutics directed toward increasing patient awareness of cyclic patterns in symptom complaints, for example, via the use of daily symptom diaries may be a useful adjunct to dietary, pharmacological, and other therapies.

[Measurement of colon transit time useful in the evaluation of functional constipation]

OBJECTIVE

To determine the colon transit time (CTT) in patients complaining of functional constipation and the correlation between abnormal transit times and the types of constipation and of the symptoms.

DESIGN

Retrospective, descriptive.

SETTING

Department of Surgery, University Hospital, Nijmegen, the Netherlands.

METHOD

The signs and symptoms of 112 patients with infrequent or difficult defaecation, 93 (83%) of them women, with a median age of 42 years (range: 16-72), were recorded by means of a questionnaire. After ingestion of radiopaque markers per day for 10 days, an abdominal survey X-ray was made on day 11. The numbers of markers in the X-ray and per segment (right and left hemicolon and rectosigmoid) were counted; the CTT in hours was calculated by multiplying this number by 2.4. Slowness was defined as more than 45 h for the total CTT and as more than 15 h for the segmental CTT.

RESULTS

The total CTT was normal in 33 patients (29%) and prolonged in 79 (71%). The CTT was prolonged only in the rectosigmoid in 14 patients with a normal CTT (42%) and in 50 patients with a prolonged total CTT (63%). Of the patients with a normal total CTT, 13 (39%) had a normal segmental CTT. No statistically significant correlation could be demonstrated between the presence of any symptom and a prolonged CTT.

CONCLUSION

Functional constipation may be associated with a normal CTT. Disorders of colonic motility and of rectal evacuation could be distinguished by measuring the total and the segmental colonic transit times.

Relation of colonic transit to functional bowel disease in older people: a population-based study

OBJECTIVE

The pathophysiology underlying chronic constipation in older people is poorly understood. Our objective was to determine if functional bowel disease (particularly constipation) in this population is associated with risk factors (age, immobility, low dietary fiber intake, and medication use) or directly with slow colonic transit.

METHODS

A previously validated questionnaire was administered to a random sample of older residents (age range 65-104 years, n = 1609) of Olmsted County, MN. A random subset who met standard diagnostic criteria for functional constipation (n = 52) or irritable bowel syndrome (IBS) (n = 55) and a group without gastrointestinal symptoms (n = 93) were selected for further study. Each subject underwent structured interview and physical examination. Total caloric and fiber intake were assessed by dietitian interview, a food frequency questionnaire, and a food diary. Physical activity was assessed using a previously validated instrument. Medication use was determined by self-report, physician interview, and review of medical records. Total and segmental colonic transit was assessed radiographically using radioopaque markers.

RESULTS

Total colonic transit times were prolonged in subjects with functional constipation (median 50.4 hours) but not in subjects with IBS (median 34.2 hours) or in healthy controls (median 28.8 hours); however, only rectosigmoid transit was delayed significantly. Age, gender, physical activity, and dietary fiber intake were not associated with total transit times, nor could they discriminate among the three patient groups. Laxative use was associated with prolonged total transit times independent of patient group.

CONCLUSIONS

Older subjects can be classified by abdominal pain and bowel symptoms, which reflect colonic transit times. Older subjects with constipation symptoms generally have prolonged rectosigmoid transit. Other potential risk factors do not distinguish symptom subgroups, nor are they associated with altered colonic transit although older people who use laxatives regularly have prolonged colonic transit.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a cluster of abdominal complaints frequently encountered in the primary setting. It is the most common gastrointestinal complaint seen in primary practice and accounts for 50% of referrals to gastroenterologists. Although the pathology of the disease currently is unclear, the diagnosis is not one of exclusion. When confronting this clinical syndrome of abdominal pain, bloating, flatulence, and changes in bowel habits, the clinician is called upon to balance the need to rule out organic causes with the expense and risk of testing. Optimally, the clinician can use established guidelines that clarify the most efficient approach to diagnosing and treating IBS, while providing the patient with the reassurance and education needed to deal with this chronic disease. This article deals with the pathophysiology, diagnosis, and management of IBS.

Gastroparesis and small bowel dysmotility in irritable bowel syndrome

Alterations in both gastric emptying (GE) and small bowel motility have been reported in irritable bowel syndrome (IBS); the relationship, however, between these different measures of upper gut motor function in IBS has not been assessed. The aims of this study were therefore: (1) to compare the prevalence and characteristics of altered small bowel motility in IBS patients with and without delayed GE; and (2) to assess the interrelationships between fasting and postprandial small bowel motility in IBS, accounting for delayed GE. Forty-four IBS patients and 25 healthy controls underwent 24 hr ambulant recording of interdigestive and digestive small bowel motility. On a separate occasion the IBS patients had GE of both solids and liquids measured by a dual-isotope scintigraphic technique. Thirty-nine percent of IBS patients had delayed GE. Patients with normal GE had no interdigestive small bowel abnormalities. However, in patients with delayed GE fasting phase II burst frequency was higher than in controls [median 0.21/hr (IQR 0.15-0.34) vs 0.06/hr (0-0,16), P = 0.004]. Postprandially, abnormal phase III-like activity was higher in diarrhea-predominant IBS patients (0-0.08/hr vs 0/hr, P = 0.01), than in patients with normal GE or controls. Furthermore, IBS patients with delayed GE did not have the normal correlation between fasting and postprandial motor parameters (percentage occurrence of clustered contractions, postprandial pattern duration vs preceding MMC cycle length). In conclusion, small bowel motor dysfunction occurs more frequently in IBS patients with concomitant gastroparesis than in patients with normal GE. These findings provide further evidence that a neuropathic process may contribute to the pathogenesis of IBS in a subgroup of IBS patients.

Evidence for two distinct perceptual alterations in irritable bowel syndrome

BACKGROUND

Visceral hyperalgesia has been implicated as a factor contributing to symptom generation in irritable bowel syndrome (IBS). However, previous studies using intestinal balloon distension have used psychophysical procedures which do not provide adequate and unbiased measures of visceral sensitivity.

METHODS

Three psychophysical tasks were examined in 45 patients with IBS (positive Rome criteria) and 14 controls using rectal balloon distension with a computerised distension device. Discomfort threshold and tolerance were assessed during an ascending series of phasic pressure stimuli and during an interactive threshold tracking procedure. In addition, stimulus response functions were generated from intensity and unpleasantness ratings of the rectal distensions.

RESULTS

Discomfort threshold and tolerance for the ascending stimuli were significantly lower for the patients with IBS compared with the controls. In contrast, discomfort thresholds during the tracking procedure and stimulus response curves for the ascending series were not different between the groups. A factor analysis of the psychophysical data was consistent with the presence of two distinct and unrelated perceptual alterations related to rectal distension: hypervigilance for visceral stimuli, manifested as lowered response criteria for using the descriptor "discomfort"; and rectal hypersensitivity, manifested as a lower discomfort threshold and left shift of the stimulus response curves.

CONCLUSIONS

Patients with IBS as a group have a greater propensity to label visceral sensations negatively and show a lower tolerance for rectal balloon distension. A subgroup of patients also have baseline rectal hypersensitivity, assessed by unbiased measures of discomfort threshold and stimulus intensity judgements.

Effects of oral cisapride on small bowel motility in irritable bowel syndrome

BACKGROUND

Cisapride has been reported to improve symptoms in patients with constipation-predominant irritable bowel syndrome.

AIM

To compare the effects of a 24-h oral dose regimen of cisapride on interdigestive and post-prandial small bowel motor activity in irritable bowel syndrome patients with predominant constipation, irritable bowel syndrome patients with predominant diarrhoea and healthy subjects.

METHODS

In 12 irritable bowel syndrome patients (11 females, aged 44 +/- 12 years)--constipation-predominant (irritable bowel syndrome-C, n = 5) and diarrhoea-predominant (irritable bowel syndrome-D, n = 7)--and six healthy subjects, small bowel motor activity was continuously recorded using an ambulatory technique over a 48-h period. Subjects received, in single-blind fashion, placebo tablets q.d.s. in the first 24 h then cisapride 10 mg q.d.s. in the second 24 h. Additional control groups were 13 healthy subjects (eight females, aged 39 +/- 13 years) and 10 irritable bowel syndrome patients (10 females, aged 49 +/- 14 years) who were studied in identical fashion but who did not receive cisapride.

RESULTS

Cisapride increased migrating motor complex phase 2 motility index in both irritable bowel syndrome-D (P < 0.01) and irritable bowel syndrome-C (P < 0.05) patients, as well as in healthy subjects (P < 0.01). An increase in fasting discrete clustered contractions occurred in irritable bowel syndrome-D patients (P < 0.001) and in healthy subjects (P < 0.01), but not in irritable bowel syndrome-C patients; the proportion of discrete clustered contractions that were propagated, however, increased only in irritable bowel syndrome-D patients (P < 0.001). In addition, cisapride resulted in an increase in post-prandial motility index in irritable bowel syndrome patients (P < 0.05). Such motor alterations were not observed during the 48-h recording period in the healthy or irritable bowel syndrome patient control groups who did not receive cisapride.

CONCLUSIONS

Oral cisapride influences interdigestive and post-prandial small bowel motor activity in both irritable bowel syndrome patients and healthy subjects; the effects of cisapride may be more marked in patients with predominant diarrhoea than in patients with predominant constipation.

Psychophysiological response to a laboratory challenge in women with and without diagnosed irritable bowel syndrome

The purpose of this study was to describe and compare physiological variables at baseline and in response to laboratory stress among women diagnosed with irritable bowel syndrome (IBS, n = 26), women with undiagnosed chronic gastrointestinal symptoms consistent with IBS (IBS-NP, n = 24), and asymptomatic women (n = 22). Urine catecholamine levels were measured in the first voided specimen on the morning of testing. Cardiovascular variables were measured at baseline and repeatedly during the Stroop Color-Word Conflict Test (Stroop). Women in the IBS group had higher baseline systolic blood pressure (SBP) than the control group and higher basal urine norepinephrine (NE) levels than the IBS-NP group. Control for activity or body mass reduced the group difference in SBP to nonsignificance but did not affect the observed difference in urine NE. There were no significant differences among the groups in other baseline values or in response to the Stroop. These results suggest that, despite higher basal urine catecholamine levels, cardiovascular reactivity to a cognitive challenge in a laboratory setting is not elevated in women with diagnosed IBS.

Sleep and gastric function in irritable bowel syndrome: derailing the brain-gut axis

BACKGROUND

Recently, several studies have shown an alteration in bowel function during sleep in patients with irritable bowel syndrome (IBS), and a recent study also suggests a remarkable increase in rapid eye movement (REM) sleep. These studies have suggested that an alteration in CNS function may play an important role in the pathogenesis of IBS.

AIMS

To confirm the presence of an alteration in REM sleep in patients with IBS and to assess the relation between sleep and a non-invasive measure of gastric functioning, the electrogastrogram (EGG).

PATIENTS

Ten patients with IBS and 10 age and sex matched normal volunteers.

METHODS

All subjects slept one night in the sleep laboratory and underwent polysomnographic monitoring to determine sleep patterns, and recording of the EGG from surface electrodes.

RESULTS

The IBS group had a notable and significant increase in the percentage and duration of REM sleep (p < 0.05). The control group had a decrease in the amplitude of the dominant EGG frequency from waking to non-REM sleep (p < 0.05), and a subsequent increase in the amplitude from non-REM to REM sleep (p < 0.05). No such changes were noted in the patients with IBS.

CONCLUSIONS

Results confirmed the enhancement of REM sleep in patients with IBS and suggested an intrinsic alteration in autonomic and CNS functioning in patients with IBS.